Animals too, remember their past

Humans possess the ability to compare the past with the present, which gives them an evolutionary advantage, helping them make better decisions. A new study, conducted by a team of researchers at the University of Bristol revealed that some animals may have this ability too, just like humans.

The study, published in the journal Science, and led by Professor John McNamara in Bristol's School of Mathematics, managed to reveal how animals behave when they are uncertain about an environmental change.

Being sensitive to past experiences and conditions is important, and it helps the animal evolve and make better decisions for survival, the scientists claim.

The team of researchers started by building a mathematical model to explain how animals should react when exposed to conditions different from that what they usually face.

"The effects in our model are driven by uncertainty. In changing environments, conditions experienced in the past can be a valuable indicator of how things will be in the future," Dr Tim Fawcett, a research fellow at the Bristol's School of Biological Sciences, said.

Strangely, they discovered that animals, who are used to living in rich conditions, when suddenly exposed to poor conditions, work less hard than those exposed to poor conditions all through their lives.

A similar study was done in the 1940s, where rats that were fed lavishly worked less hard to get small amounts of food than those who were used to getting small amounts of food.

This 'contrast effect' is not just limited to mice, but is also found in bees, mammals, including newborn children and starlings. This very effect was not understood by scientists until now; however, Dr Fawcett seems to have an answer.

"An animal that is used to rich conditions thinks that the world is generally a good place," he explained. "So when conditions suddenly turn bad, it interprets this as a temporary 'blip' and hunkers down, expecting that rich conditions will return soon. In contrast, an animal used to poor conditions expects those conditions to persist, and so cannot afford to rest."

What's more, this theory works the other way round too. Animals exposed to rich conditions work less hard when their conditions get better, as compared to those living in poor conditions.

In general, this study has definitely managed to highlight the importance of unpredictable evolutionary factors in stimulating evolution.

"The natural world is a dynamic and unpredictable place, but evolutionary models often neglect this. Our work suggests that models of more complex environments are important for understanding behavior," Dr Fawcett concluded.